Dissertation Project for the Forensic Science Laboratory: Birch Reduction of Ephedrine and Analysis of Byproducts of Forensic Science Interest

Abstract

This undergraduate dissertation project was designed to enhance organic and analytical chemistry skills of final year forensic science students. A modified Birch reaction method was employed to synthesize amphetamine from ephedrine and detect the most known byproduct of clandestine manufacture of amphetamines, e.g., 1-(1,4-cyclohexadienyl)-2-methylaminopropane (CMP). The use of this synthetic method led to simultaneous N-demethylation and dehydroxylation of the alkaloid. Harmful liquid ammonia and lithium metal, which are the typical reagents of the classic Birch reaction, were replaced by the safer sodium silica gel stage I (Na-SG-I) and an alcoholic proton source. Liquid chromatography–mass spectrometry (LC-MS) was used to monitor reaction progress and identify starting material, products, and byproducts, whereas proton and carbon nuclear magnetic resonance (1H and 13C NMR) and heteronuclear single-quantum correlation (HSQC) NMR spectroscopy experiments were employed to characterize amphetamine and the parent compound ephedrine. This multiweek project-based learning experience has been running for three years at De Montfort University (DMU), which offers a well-established Forensic Science BSc (Hons) undergraduate course. The students were guided with the help of an academic instructor through a research-like setting delving into synthesis, characterization, and analysis of a drug of abuse and its byproduct. As part of this learning experience, which culminated in a body of work that informed the content of final year dissertations, the students gained useful organic chemistry skills and consolidated previously acquired knowledge in trace analysis. A survey of the dissertations’ final grades and evaluation of end-of-project questionnaires revealed that students responded well to the challenges posed by the organic chemistry aspect of the lab and that the project topic and methods were engaging and very relevant to the forensic science course.